Means for testing compression strength of materials



April 27,1937. s, VADNE 2,078,296

MEANS FOR TESTING COMPRESSION STRENGTH OF'MA'I'ERIALS Filed Oct. 19; 1934 IIIHIHIWW -a 7am --innnm|mm-n mnmm u um: l- IIIHIIHIII w SamuZ Viza n er Attorneys Patented Apr. 2 7, 193.7

UNITED STATES MEANS FOR TESTING COMPRESSION K STRENGTH OF MATERIALS Samuel Vadner. .Crestwood, N. Y.

Application October 19,1934, Serial No. 748,993

4. Claims.

This invention relates to a means for testing the resistance to compression of materials such as corrugated paper board, rubber or other -compressible materials.

It is an object of the invention to provide a dependable means for. testing the compression strength of compressible materials. I

It is a further object to provide a means of measuring both the resistance to compression of such materials and the extent of the compression.

It is a further object of the invention to provide certain improvements in the well known Mullen tester" which will permit it to be used for testing the compression strength of compressible materials, in addition to its present use of testing the bursting strength of materials.

One illustrative means is disclosed in the drawing, in which:--

Figure 1 is aperspective view of an apparatus embodying the invention.

Fig. 2 is an enlarged side elevation of the upper compression plate.

Fig. 3 is a plan view of the bottom surface or the upper compression plate.

Fig. 4 is a side elevation of the lower compression plate.

Fig. 5 is a top plan view of the lower com pression plate.

Fig. 6 is a side elevation partly in section of the upper and lower plates associated together with a strip of corrugated fiberboard interposed between the two plates.

Fig. '7 is a perspective view of the well known "Mullen tester.

Referring to Fig. '7 the Mullen tester there shown is supported by a base member I. Carried by the base member I is a horizontal cylinder member 2 having an upwardly extending portion 8 carrying a disc 4 to support the material to be tested. Disc 4 is provided with a central opening 5 beneath which is located a rubber diaphragm adapted to expand upwardly through the opening 5 when pressure is disc 4. The arm 8 carries a semi-spherical mem-- ber 9 .which may be raised and lowered by tuming a handle l0. Member 9 is secured to handle Ill by a bolt Illa. The piece of material to be tested is placed on the disc 4 and the member 9 is lowered to clamp the piece of material on the disc '4. The wheel 6 is then turned to increase the fluid pressure against the bottom of the rubber diaphragm, causing the diaphragm to press upwardly in the form of a spherical segment through the opening 6 and to press against the material being tested. Continued fluid pressure will cause the spherical segment of the diaphragm to burst through the material being tested. The gauge 1 indicates the pressure of the fluid in pounds per square inch at the time the diaphragm bursts the material or breaks through it.

From this brief description of the well known Mullen tester it will be seen that the Mullen tester is adapted to test the resistance of material to a bursting pressure. It is an object of the present invention to provide an attachment which may be used in the Mullen tester to test the resistance of materialto compression.

The attachment consists of a lower compression plate H (see Figs. 4 and 5) preferably circular in shape and made of durable metal, such,

. for example,' as steel. The lower compression plate H 'is adapted to rest upon disc 4 of the Mullen tester. To prevent slippage, plate H is provided on its bottom surface and centrally oi. the disc with an extension l2 to flt into the open ing 5 of the disc 4. The bottom of extension I2 is cut away to form a spherical section i3 to receive the portion of the rubber diaphragm which extends upwardly through the opening 5 when the diaphragm is forced therethrough by the pres sure thereagainst.

The upper surface of the lower plate ii is preferably provided with upwardly extending rim members It to retain the material to be tested on the plate ll. Extending from one side of the plate H is a pin l5 for operating the gauge which indicates the extent of the compression, all as hereinafter described. I

Referring to Figs.'2 and 3, the upper compression member consists of a plate l8 preferably of durable metal such as steel and shaped to correspond to the shape of the lower compression plate ii and adaptedto fit within the rim members M of the lower plate ll. Extending upwardly-from the center oi! plate I6, is a threaded shaft l1 secured to the handle ill of the Mullen tester by means of the bolt Illa as shown in Fig. 1. Thus the upper compression plate may be readily substituted for the member 9 of the Mullen tester.

For measuring the extent of the compression at zero so that when the lower plate Ii is raised by pressure exerted on the rubber diaphragm, the

micrometer will indicate the extent of the up- .ward movement of the plate I I, and hence the extent of the compression oi the material 1?- ing upon the plate H.

I The operation of the compression testing apparatus will be apparent from the foregoing description. A piece of corrugated fiberboard such as that shown at I 8 in Fig. 6 is out to the size or the lower-plate H, and the lower plate Ii with the fiberboard thereon is positioned on the disc 4 oi the tester. Handle it is then rotated to lower upper compresslonplate ll into firm contact with the corrugated fiberboard. v'Ihe micrometer is then set to zero. The wheel 6 is then turned to exert liquid pressure against the rubber diaphragm which causes the rubber diaphragm to extend upwardly throughthe opening 5 in the disc 4 to, press against the lower compression plate I'l, thus raising the plate II and compressing the fiberboard located between the lower plate It and the upper plate I. Durin the increase in the fluid pressure the gauge 1 registers the amount of the pressure and hence the resistance of the material to compression.

It should be noted that the compression plates 35 engage and clamp between them a comparatively wide area of the material to be tested. and thus permit a compression test as distinguished from a bursting test through the pressure exerted by the rubber diaphragm of the Mullen tester.

It should also be noted that the apparatus of this invention may be used to test the fatigue" y, resistance of compressible materials. For example, a pieceo! corrugated board can be sublected to a' certain. pressure (not sumcie'nt to entirely crush the material) for a period of time (one or more hours) and then additional pressure applied suillcient to completely crush the material. Thus the resistance to acontinuing pressure ma be determined.

It will beunderstoodthat the invention is not to be limited to the specific embodiment shown for purposes of illustration. For example. the compression plates need not be circular in form.

It will also beunderstood that all or the iea- 55 tures of the invention need not be used coniointly as they may be used in various combinations as deilned inthe sub-Joined claims. 7

I claim: v

After the air/spas 1. In apparatus for testing the compression strength of corrugated paper board. the combination of a lower compression plate provided with an upwardly extending rim to receive the corrugated paper board and confine the layers thereof against relative shifting during. compression of the board, an upper plate adapted to fit within the rim or the lower plate and to clamp the board on the lower plate, meansto hold the upper plate against movement during atestin operation, a rubber diaphragm adapted to engage the central'portion oi the under side of the lower plate, means to press the diaphragm against the lower plate to raise it, means to indicate the amount of pressure, and means to in- -'dicate the extent of movement of the lower plate.

2.-In apparatus for testing. the compression strength of corrugated paper board, the combination of a lower compression plate provided with an upwardly extending rim to. reteive the corrugated paper board and confine the layers-thereof against relative shitting during compression of the board, an upper plate adapted to fit with-.-

in the rim of the lower plate arid to clamp the board on the lower plate, means to hold upper plate against movement timings testing operation, a rubber diaphragm adapted to engage the central portion of the under side oiv the lower plate, means to press the diaphragm against the lower plate to raise it, and means to indicate the amount or pressure. i i

3. In apparatus for testing thecompresslon strength of corrugatedpap'er board, a pair or compression plates adapted to clamp between,

them a piece of corrugated paper board. one of said plates being provided with a; rim to prevent sidewise shifting of the layers oi. corrugated board, and the other of said plate; being. adapted to tit within said rim, a rubber diaphragm, means to press the diaphragm against one plate to move it toward the other plate to crush the material therebetween, and means indicating the extent of such movement and the pressure required to crush the material. I

4. In apparatus ior testing the compression strength of corrugated paper-board, a pair of compression plates adapted to clamp between them a piece of corrugated paper boar-drone oi said plates being provided with a rim to prevent sidewise shifting of the layers or corrugated board. and the other or said plates being adapted to tit within said rim. a rubber means to press the diaphragm against one plate to move it toward the other plate to crush the material therebetween, and means indicating the pressure required to crush the material. x m VADNIR. 

